• Steel and Composite Structures
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• v.37 no.3
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• pp.323-339
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• 2020

In steel framed-tube structures (SFTSs), the plastic hinges at beam-ends cannot be adequately improved because of the large cross sections of spandrel beams, which results in the lower ductility and energy dissipation capacities of traditional SFTSs. To address this drawback, high-strength steel fabricated SFTSs with bolted web-connected replaceable shear links (HSFTS-SLs) have been proposed. In this system, shear links use conventional steel and are placed in the middle of the deep spandrel beams to act as energy dissipative components. In this study, 2/3-scaled HSFTS-SL specimens were fabricated, and cyclic loading tests were carried out to study the seismic performance of both specimens. The finite element models (FEMs) of the two specimens were established and the numerical results were compared with the test results. The results showed that the specimens had good ductility and energy dissipation capacities due to the reliable deformation capacities. The specimens presented the expected failure modes. Using a shorter shear link can provide a higher load-carrying capacity and initial elastic lateral stiffness but induces lower ductility and energy dissipation capacity in HSFTS-SLs. The performance of the specimens was comparable to that of the original sub-structure specimens after replacing shear links. Additionally, the expected post-earthquake recoverability and resilience of the structures could be achieved by replacing shear links. The acceptable residual interstory drift that allows for easy replacement of the bolted web-connected shear link was 0.23%. The bolted web-connected shear links had reliable hysteretic responses and deformation capacities. The connection rotation had a notable contribution to total link rotation. The results of the numerical analysis run for the proposed FEMs were consistent with the test results. It showed that the proposed FEMs could be used to investigate the seismic performance of the HSFTS-SL.

• Fashion & Textile Research Journal
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• v.15 no.6
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• pp.985-992
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• 2013

Polytrimethylene terephthalate(PTT) offers several advantageous properties such as good tensile strength, uniformity, stiffness, toughness, UV stability, resilience, stain resistance, outstanding elastic recovery, and dyeability. The effects of annealing temperature on physical properties and the structure of PTT filaments and yarn were investigated by measuring wide-angle X-ray diffraction (WAXD), density, optical birefringence, dynamic visco elasticity, and tensile testing. The intensity of maximum tan ${\delta}$ decreased and the temperature of maximum tan ${\delta}$ shifted to a higher temperature as the annealing temperature of filaments increased; however, it shifted to a lower temperature when the annealing temperature exceeded $130^{\circ}C$. In addition, crystallinity, density and D-spacing of (010) crystal face increased as the annealing temperature increased. Optical birefringence and specific stress were almost constant up to $100^{\circ}C$ and then decreased above $130^{\circ}C$. The shrinkage of PTT filament is 0 in boiling water when annealed above $130^{\circ}C$; consequently, the use of annealed fiber above $130^{\circ}C$ can remove thermal instability when dyeing PTT fiber. In the case of yarns, the thermal stability and physical properties of yarns showed the best effect when the ply number is less than 5, twist number is less than 400tpm, and the annealing time is 20minutes.

• Journal of the Korean Society of Costume
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• v.57 no.2 s.111
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• pp.1-10
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• 2007

This study aims at the improvement of sewing function through understandings of dynamic property about the sewing methods and the thread material selection in knitwear. The tensile strength and shear of KES-FB and the Instron were measured for the analysis of the mechanical properties. The knit cloth was structured In the plain stitch, $1\times1$ rib stitch and $2\times1$ rib stitch with the combination of wool and cotton. With regard to the sewing method, intralooping and interlacing were applied. For thread materials, polyester, cotton, wool and silk were used. Since silk has the lowest extension and similar values regardless of its construction in intralooping, it is available knit apparel with uniform elastic recoverv. It also has small shearing resistance. It can be used in apparel which needs big mobility, but it causes rutting problem. Therefore, it is suitable to use intralooping. When the same sewing yarn and textile are use, it can lower shearing resistance and extension in intralooping, Since wool needs a lot of extension energy and it can be cut, intralooping is more suitable than interlacing in sewing of wool. In interlacing using polyester, extension and shearing resistance are high. Therefore, it is suitable for knit sewing with high massing. Silk is not suitable for interlacing since it can be rut. Even though knit materials are different, the RT values of polyester and cotton are similar in same construction. Therefore, they can be substituted each other considering resilience after sewing.

• Journal of Industrial Convergence
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• v.18 no.5
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• pp.54-61
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• 2020

The purpose of this study was to understand the effect of job stress of female caregivers working in home-based elderly welfare centers on turnover intentions and to understand the moderating effect of self-elasticity in these relationships. The subject of the study was a self-written questionnaire survey of 170 nursing care workers at 28 home-based elderly welfare centers in Seoul, and 150 copies were collected and 133 people were finally analyzed excluding 17 unscrupulous responses. As a result of the study, first, the average value of turnover intention was high in the group with low experience of female caregivers at home-based elderly welfare centers and the group without religion. Second, the higher the job stress of nursing care workers, the higher the intention of turnover. Third, there was a moderating effect of self-elasticity between the job stress and the of turnover of nursing care workers. Therefore, it was necessary to consider measures to prevent job stress of nursing caregivers and improve self-resilience.

• Journal of the Society of Disaster Information
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• v.15 no.2
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• pp.206-213
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• 2019

Purpose: This study aims to develop eco - friendly paving materials using Sawdust and EPDM chips. Method: Materials are eco-friendly materials and have no environmental problems. By using EPDM chip, the walking feeling can be increased. Results: In this study, the optimum mixing ratio was calculated through mixing design test. Based on the blending ratio, the surface layer of the sidewalk is made of fine sawdust and EPDM chips. We used only sawdust of grain - 107 -size to make the base layer of the sidewalks and the surface layer of the bicycle road with the permeability and the anti - resilience, and suggested the application method through the test construction. Conclusion: This study the expected that the recent efforts of the government to reduce the elastic paving material, which is the environmentally harmful problem with the complete eco-friendly paving material, are expected to revive.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.30 no.1
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• pp.53-62
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• 2024

Molded pulp products has become more attractive than traditional materials such as expanded polystyrene foam (EPS) owing to low-priced recycled paper, environmental benefits such as biodegradability, and low production cost. In this study, various design factors regarding compression and cushioning characteristics of the molded pulp cushion with truncated pyramid-shaped structural units were analyzed using a test specimen with multiple structural units. The adopted structural factors were the geometric shape, wall thickness, and depth of the structural unit. The relative humidity was set at two levels. We derived the cushion curve model of the target molded pulp cushion using the stress-energy methodology. The coefficient of determination was approximately 0.8, which was lower than that for EPS (0.98). The cushioning performance of the molded pulp cushion was affected more by the structural factors of the structural unit than by the material characteristics. Repeated impacts, higher static stress, and drop height decreased the cushioning performance. Its compression behavior was investigated in four stages: elastic, first buckling, sub-buckling, and densification. It had greater rigidity during initial deformation stages; then, during plastic deformation, the rigidity was greatly reduced. The compression behavior was influenced by structural factors such as the geometric shape and depth of the structural unit and environmental conditions, rather than material properties. The biggest difference in the compression and cushioning characteristics of molded pulp cushion compared to EPS is that it is greatly affected by structural factors, and in addition, strength and resilience are expected to decrease due to humidity and repetitive loads, so future research is needed.

• Progress in Medical Physics
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• v.20 no.2
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• pp.80-87
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• 2009

Phase transformation, superelastic characteristics and variation of surface residual stress were studied for Nitinol shape memory alloy through application of UNSM technology, and life extension methods of stent were also studied by using elastic resilience and corrosion resistance. Nitinol wire of ${\phi}1.778$ mm showed similar surface roughness before and after UNSM treatment, but drawing traces and micro defects were all removed by UNSM treatment. It also changed the surface residual stress from tensile to compressive values, and XRD result showed less intensive austenite peak and clear martensite and additional R-phase peaks after UNSM treatment. Fatigue resistance could be greatly improved through removal of surface defects and rearrangement of surface residual stress from tensile to compressive state, and development of surface modification system to improve not only bio-compatability but also resistance to corrosion and wear will make it possible to develop vascular stent which can be used for circulating system diseases which run first cause of death of recent Koreans.